Invidia Test Pipe 2000+ Honda S2000 (Cel-fix) - P/N: HS00HS1TP2 Product Model: INV-HS00HS1TP2 Pipe Size: 70mm (Cel-fix) Invidia test pipes are designed to dramatically improve engine performance and increase horsepower by significantly reducing exhaust flow restriction. Made from mandrel-bent aircraft quality 304 stainless steel and precision TIG welded.